Expanding for use in tubular magazines

[BillR]

Clause 3.2(xv) of the April 2016 guide defines expanded ammunition designed or adapted to expand on impact. The guidance acknowledges the fact that bullets expand on impact but the guidance points specifically to the design intent of the bullet manufacturer. Jacketed bullets are usually used to allow the bullet to reach greater velocity without stripping lead from the bullet due to friction burn. This would apply more to soft lead cores rather than hard cast bullets without the jacket although velocity is the key here methinks. The guidance also suggests consulting the manufacturer to determine if the bullet is designed to expand on impact or not.
It takes a bit of deciphering as you are referred to different clauses along the way. Definitions are in Clause 4.2 and especially 4.3.
BillR.

[Sim G]

No, the paragraph referenced is 3.21

"3.21 Category (xv) refers to ammunition incorporating a projectile that is designed or adapted to expand in a controlled manner. It is the kind of ammunition used in deerstalking and vermin control because it is more likely than non-expanding ammunition to ensure a quick and humane kill. Semi-jacketed soft point and hollow point are typical forms of expanding ammunition, but care must be taken to distinguish between match target hollow point ammunition, which has a tiny hole at the front for manufacturing purposes, and true hollow point. Match hollow point rounds which are not designed to expand upon impact, such as the Sierra Match King and the Hornady A-Max, are not prohibited. Flat-nosed bullets, which are designed to prevent a magazine explosion caused, by a pointed bullet resting on the primer of the cartridge ahead of it when the ammunition is used in a tubular magazine are also not prohibited. All bullets will distort on impact, but only those which were designed or adapted to do so in a predictable manner fit this category."

[BillR]

3.2(xv) is the correct Clause as it comes first and 3.21 is the further expanded explanation to clarify 3.2(xv). Official documents are always like this. They never give a full explanation which is why you have to go to other clauses in the guidance to properly come to a conclusion. It does make it easier to update as you only require to modify the specific clause(s) that are being updated rather than the whole document numbering system

BillR

[Sim G]

I'm really not sure what point your trying to make, but honestly you sound confused. Para 3.2 is nothing more that a replication of s5 (as amended) Firearms Act 1968. Para 3.21 is advice on how the police should administer the legislation together with the vagaries of particular firearm use.

Velocity, jackets and what have you is immaterial.